Pressure-control device for switches



J. H. DENNEDY PRESSURE CONTROL DEVICE FOR SWITCHES Filed June 29;

nQento'l James H vewnady PATENT OFFICE.

JAMES H. DENNEDY, 0F DETROIT, MICHIGAN rnnss'nnn-oonrnon DEVICE r012.swrrcnm.

Application filled June 29, 1922. Serial No. 571,680.

To all whom itmay concern:

Be it known that 1,. JAMES H. DENNEDY, a citizen ofthe United States,residing at Detroit, county of lVayne; State of Michigan, have inventeda certain new and useful Improvement in Pressure-Control Devices forSwitches, and declare the following to be a full, clear, and exactdescription of the same, such as will enable others skilled in the artto which it pertains to make and use the same, reference being bad tothe accompanying drawings, which form a part of this specification. p

This invention relates to pressure controlled switches for refrigeratingsystems or other apparatus carrying a, fluid under a varriable'pressure, and the object of the invention is to provide a switchmechanismand apparatus for operating the switch controlled by thepressure of fluid as for instance the fluid in the low pressure side ofthe circulating system for an artificial refrigerating apparatus. Theparticular features of the invention are involved in the structure andrelationship 'of parts of the control mechanism subject to influence ofvariation of pressure and in the combination therewith of an electricswitch for making and breaking the circuit of an electric motoroperatingthe apparatus. These objects and the. several novel features ofthe invention are hereinafter more fully described and claimed, and thepreferred form of construction of a device embodyingm invention is shownin the'accompanying' rawings in which I Fig. 1 is a verticallongitudinal section of my improved switch and control apparatus showingthe switch open.

Fi 2 is a similar'view showing the switch closed. I

Fig. 3 is a plan view of the switch mechanism.

In the usual artificial refrigerating system, a compressor is utilizedin conjuction with a circulating system having a high and low pressureside and an electric motor for operating the compressor. Thisstructureembodies the combination with a switch device for making andbreaking the circuit of a motor of apparatus sub'ect to influence ofvariation in pressure of t e low pressure side of the circulating systemand while the refrigerating system in its entirety has not here beenshown the operation-of the device will be readily understood by thosefamiliar with the art. The low pressure line of the circulating systemis indicated at 1 and a branch 2 leads from this line to the casing 3 ofthe control device. Within this case is a deeply corrugated cylindricalbellows member iknown to the trade asa sylphon, the lower end of whichis sealed to a plate 5 and the upper. end of which is sealed to a plate6 that is securely fastened between the cap member 7 and the flange 8 ofthe easing 3. This provides a chamber 9 between the bellows member andwall of the member 3 sealed to atmosphere into which the line 2 opens Itis to be observed that I have shown the line 2 as being the low pressureside of the circulating system of artificial refrigerating apparatuswhereby the chamber 9 is subject to variation in pressure, but it is tobe understood that any approved means may be employed to vary thepressure in the chamber 2 by a temperature change as for instance theWell known method of supplying a volatile fluid in the chamber vaporizinunder certain high temperature and condensing under low temperature orthe usual sensitive bulb may be employed connected to the apparatus inthe same manner as here'shown with the line 2. The plate 5 at the lowerend of the bellows member is secured and sealed to the central shaft 10which extends upward through a threaded plug 11 in the\upper end of thecap member. This member 11 is provided with a central square orhexagonal aperture 12 and. the

shaft is threads to receive a nut 13 flanged at the lower end as shownand having a square or hexagonal body that may enter the aperture 12 ofthe plug 11.- The threads -on the outside of-the plug 11 and the threadson the inside of the nut 13 have the same pitch and number of threadsper inch. The plug 11 is preferably provided with a series of apertures14 for insertion of. a pin to be utilized in turning the nut or plug,and the plug 11 and nut 13 providefor an adjustment without altering.the relative positions of plug 11 and the nut 13 as is hereinafterstated. Within the bellows member and about the shaft 10 is a coiled.compression spring 15 seating against the plate 5 at the bottom and in,the plu '11 at the top and tend to force the mem er 5 downward expandingthe bellows member. The switch is so constructed that this'movementdownward by the spring forces the shaft 10 downward due to ltS'attachment to the bellows member and opens the switch and on the contrapressure developing in the pipe line 1 and dliamber 9 forcesthe plateupward against the tension of the spring compressing the bellows raisingthe shaft 10 which closes the switch.

The character of the electric switch structure is not material to thisinvention as various structures can be utilized that will make or breakthe circuit by movement of the shaft 10. The preferred type of switchhere shown comprises a base 16 of insulating material that is carried onthe cap member 7 by means of studs 17 of which there are several. Onthis base is mounted a frame consisting of the side plates 18 and 19 aswill beunderstood from Fig. 3. A shaft 20 extends through the two sideframes at one end and on the outer side of each frame is pivotallymounted a lever 21 formed at the rear end with outturned flanges 22 and23 in'V form and also with terminal out turned flanges 24 and .25. Theend 26 of each lever 21 is adapted for engagement with the respectivecontact member 27 or 28 as the case may be; there being two levers 21and a contact member 27 and 28 for the res ective levers. The circuit90, 91' of the e ectric motor is connected with these contacts 27 and 28and when the end 26 of the levers 21 is passed between the blades of themembers 27 and 28 the circuit is completed. The levers 21 are operatedbythe U member 29 pivotally mounted on a shaft 30 extending through thetwo frame members 18 and 19 and the ends 31 of this member 29 liebetween the flanges 22, 23 etc,

of the pin 32 extends between the adjacent ends of these two parts ofthe levers 34 as will be understood from Fig. 3. Near the pivot point ofthe lever 34 is a shaft- 36 extending between the two parts of the lever34 and pivotally mounted on this shaft and extending downwardlytherefrom is a link 37 which is pivotally connected at 38 with a link 39which in turn is pivoted at 40 to a link 41 pivotally sup orted on theshaft 30. There are prefera 1y two links 39 and supported therebetweenis a shaft 42 on which is pivotall mounted the threaded stub shaft 43. Te upper end of the shaft 10 of the -control device, as will beunderstood from Fig. 1, has a threaded portion 44 and a right and lefthandv threaded nut 45 is provided into which this end 44 of the shaft 10and the threaded end of the shaft 43 extend thus connecting the links 39with the shaft 10.

The two part lever 34 above mentioned has an arcuate slot 45 near theend to which the pin 32 is pivoted and through this slot extends theshaft 30 and which limits the movement of the composite lever 34 on itspivot. 1th the parts in the position shown in Fig. 2, pressure in theline 1 has raised the plate 5 and shaft 10 closing the switch andcompleting the circuit. This movement of the parts is from the positionshown in Fig. 1 to that shown in Fig. 2. It will be seen on examiningFig. 1, that on upward movement ofthe shaft 10 due to its connection bymeans of the stub shaft 43 with the links 39 and the links 37, the lever34 would be gradually moved upward about its pivot. This movementraisesthe pivot point'33 of the pin 32 upward compressing the spring 35 and asthis ivot point passes the center line between t e aperture in the yokemember 29 and shaft 30 thereof, the spring will act to depress the endof the yoke 29 raising the opposite end 31. Due to the flanges 24 and 22the end 31 of the member 29 by engaging first against the flange 24begins to turn the lever 21 and then engages the flange 22 comparativelyclose to the pivot point of the lever 21 which causes a quick movementof the end 26 in engaging the corn tact 27. This action of the ends 31of the yoke in relation to the levers 21 is the same either in theupward or the downward movement. The upward movement is caused by of thenut 13 is below t e web of the plug 11. This flange limits the upwardmovement of the shaft 10 and plate 5 so that excess pressure in the line1 cannot be transferred to the switch machanism and by adjustment of theplug 11 and nut 13 required latitude of movement of the switch is.provided and the mechanism safeguarded from pressure The plug 11 ismade adjustable to vary the tension of the spring 15. Also the bellowsmember is prevented from too great elongation or compression as theplate 5 limits the expanding movement of the bellows member and the nut13 of the compression movement. I have here shown and described aparticular switch structure. As heretofore stated it is to be understoodthat various switch structures may be utilized with this control deviceand it is also to be understood that the switch structure may bearranged to break the circuit on an increase of pressure and to closethe circuit on a decrease of pressure in the chamber 9 which is exactlythe reverse of the operation of the switch here shown and described.

With a device of this character, control of the operation of theartificial refrigerating apparatus or other devices is secured byastructure that is simple and efficient in character and when used withartificial'refrigerating apparatus, temperature may be controlled byvariation in ressure of the low pressure line or expansion side of thesystem rather than by use of a thermostat as has ordinarily been thepractice. By setting this mechanism to close the switch upon certainincrease of pressure in the low pressure line the pressure of the lowpressure line is maintained between certain limits which determines thecooling effect. Furthermore, by use of the specific switch mechanism asherein described, a slight movement of the shaft 10 may cause themaximum movement of the switch arm 21. This occurs by reason of thepeculiarleverage utilized and in the particular relationship of theactuator member 31 and the lever 21 causing a quick make or break of thecontact. However, my pressure actuated device may be used with varioustypes of apparatus in which it is necessary or useful to make or break acircuit upon decrease or increase in pressure of a fluid subject tovariation in pressure.

-Having thus fully described my invention, what I claim 1s 1. Inpressure actuated mechanism for con- 'trol of electric switches, thecombination with. an electric switch having a member movable to make orbreak a circuit through-the switch, of a pressure controlled mechanismfor moving the member comprising a casing, a bellows like member thereinexpansible or contractible longitudinally and providing a chamber on theexterior thereof sealed to atmosphere and open to influence of fluidhaving a variable ressure, a rod secured to an end of the bellowsmember, a cap for the casing supporting the switch, said cap having anopening therethrough whereby the interior of the bellows member is opento atmosphere, the rod extending through the said aperture to ya movablepart of the switch and being threaded, a nut on the rod adjacent thesaid aperture adjustable longitudinally of the rod and limiting theextent of compression movement'of the bellows member whereby the switchmechanism is rotected from excess pressure, and a coi ed spring withinthe bellows member tending to expand the same on certain reduction ofpressure in the chamber.

2. In pressure actuated mechanism, the combination with a device movableunder control of said mechanism, of a casing comprising a body portionand a cover, a cylindrical corrugated bellows within the casing havingone end in sealed attachment to the cover, a plate closing the other endof the corrugated bellows member, a rod attached to said latter closingmember and extending outwardly through an aperture in said cover, saidaperture communication to the inner part of said corrugated member, anadjustable member fitted in the aperture in said cover, a compressionspring between said adjustable member and said plate, said adjustablemember having an aperture therein through which said rod extends, asecond adjustable member carried by the rod and arranged to abut theinner side of the adjustable member carried by the cover, said platebeing normally held against the base of said casing by said spring, andmeans for applying fluid pressure between said corrugated bellows memberand the reciprocation of said rod between the before mentioned stops.

3. In pressure actuated mechanism for control of electric switches, thecombination with a switch having a member movable to make or break acircuit'through the switch, of a casing, a bellows like member thereinhaving one end secured to the cusing, the opposite end being closed andprovi ing a chamber between the member and easing sealed to atmosphere,a cap for the casing having an aperture roviding atmosphericcommunication to the inner part of said bellows like member, anapertured plug therein in threaded relation with the 'cap, a coiledcompression spring extending between the plug and closed end of thebellows, a rod secured to the closed end of the bellows member andextending through the aperture of the threaded plug, said plug providinga means for adjusting the tension of the spring, a member on the shaftadjustable longitudinally thereof and limiting the extent of movement ofthe rod on compression of the bellows member whereby the switchmechanism is relieved from excess pressure, said rod being attached tothe movable switch member.

4. In mechanism for controlling an electric circuit in combination witha switch having a member movable to make or break the circuit, of aparatus for causing movement of the mem comprising a rod connected withthe movable member, a bellows like member expansible or'contractible byvariation in ressure, said rod being connected with t c said member, acasin enclosing the bellows member and providing providing atmosphericsaid plate for causing a. chamber between the member and the Wall of thecasing, a cap member -for the casing through which the shaft extends, aplug threaded therein having a many sided central aperture, a nutthreaded on the rod, the plug and nut having the same pitch and numberof threads per inch, the nut having a many sided portion extending intothe aperture of the plug whereby turning of 10 the plug turns the nut tolike'extent, said nut having a flange normally spaced from the plugpei'n'iitting limited movementof the rod by contraction of the bellowsmember, and a spring extending between the plug and base of the bellowsmember adjustable in tension by the turning of the plug.

In testimony whereof, I sign this specificat-ion.

JAMES H. DENNEDY.

